Finally, you need no special equipment. A jar with a lid will do, or a bowl and a whisk.

Vinaigrette is a kind of salad dressing based acid and oil. You’ve probably read that the ratio of 3 parts oil to 1 part acid (vinegar or lemon) is what you use, and that’s a good place to start. But the final proportion will always depend on just how acidic your acid is.
A strong vinegar, like sherry vinegar, needs more oil than 3:1 not to end up overly tart. Balsamic vinegar is less acidic and sweeter, so you can use less oil in proportion to it. Lemon juice is very tart. Rice wine vinegar less so. Acidity is measured in grains and one of 7% or 7 grains would be very sharp, or acidic, indeed. It will tell you the percentage on the bottle.

What this means is that you have to taste your dressing—not on your finger but on a leaf of lettuce or whatever it is you’re dressing—then adjust if need be, adding more acid if needed, or more oil. I suggest that you use the three parts oil to one part vinegar or lemon as a place to begin, but be prepared to adjust the finally amounts to suit your taste.

Combine the ingredients in a jar, give a shake to emulsify them, then taste. Adjust if needed. Or, combine the ingredients in a small bowl and whisk them together.

That’s it!

Here are some simple variations and additions.

Lemon Vinaigrette
Grate the zest off the lemon and add it to the vinaigrette. Of course you’ll use lemon juice for the acid.

Shallot Vinaigrette
Finely dice 1 shallot, one that’s not too large.
Put it in a bowl with 1/8th teaspoon salt and 1 tablespoon fresh lemon juice or vinegar – your choice. Let it stand for 5 minutes or more. This will “pickle” the shallot and make it sweeter and less harsh. Then whisk in the oil or shake it in a jar.

Mustard Vinaigrette
Whisk 1 teaspoon Dijon style mustard with the salt and vinegar, this time using a red wine vinegar. Add the oil and whisk or shake or whisk until emulsified. Taste and adjust if necessary.
Include the shallot, too, if you like.
You can also whisk in a tablespoon of sour cream or Greek yogurt.
(This is very good with vegetables from the mustard family, like broccoli.)

Herb Vinaigrette
Add fresh herbs to any of the vinaigrettes above, alone or in combination, such as snipped chives, chopped parsley or chervil, fresh oregano or marjoram, slivered basil leaves, chopped dill. Choose an herb, or herbs, that harmonizes with your dish, perhaps matching an herb that’s already used elsewhere in the meal.

And don’t forget:
1. You can make more than just 4 tablespoons at a time. Vinaigrette keeps for several days, so you can use it more than just once.

2. These basic vinaigrettes are not just for lettuce. They can transform anything into a salad —cooked grains, steamed vegetables like cauliflower, asparagus and broccoli, raw vegetables like grated carrots, and beets, celery, mushrooms, pasta —the list is long.

3. Start with good ingredients—a fresh olive oil that you like, fresh lemon, good vinegars. Eventually you might want to explore vinegars you’ve never tried before, or use vinegar in combination with one another, for they have much to do with the character of a salad.